[compositor-worker] root scrolling layer is associated with document scrolling element

third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp

Index: third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp b/third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp
index 3a90cd9b2969ebebfb078ede8abcb2f2d59692fe..020d1a557c2cf3f5854f7377c1fc6d2fd859e7bd 100644
--- a/third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp
+++ b/third_party/WebKit/Source/web/tests/CompositorWorkerTest.cpp
@@ -4,11 +4,13 @@
 
 #include <gtest/gtest.h>
 #include <memory>
+#include "core/dom/DOMNodeIds.h"
 #include "core/frame/FrameView.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/layout/compositing/CompositedLayerMapping.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/page/Page.h"
+#include "platform/graphics/CompositorElementId.h"
 #include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/graphics/CompositorMutation.h"
 #include "platform/graphics/GraphicsLayer.h"
@@ -165,7 +167,9 @@ TEST_P(CompositorWorkerTest, plumbingElementIdAndMutableProperties) {
                (CompositorMutableProperty::kScrollLeft |
                 CompositorMutableProperty::kScrollTop |
                 CompositorMutableProperty::kOpacity));
-  EXPECT_TRUE(proxiedLayer->elementId());
+  EXPECT_EQ(proxiedLayer->elementId(),
+            createCompositorElementId(DOMNodeIds::idForNode(proxiedElement),
+                                      CompositorSubElementId::Primary));
 
   Element* scrollElement = document->getElementById("proxied-scroller");
   WebLayer* scrollLayer = scrollingWebLayerFromElement(scrollElement);
@@ -175,8 +179,11 @@ TEST_P(CompositorWorkerTest, plumbingElementIdAndMutableProperties) {
   EXPECT_FALSE(scrollLayer->compositorMutableProperties() &
                (CompositorMutableProperty::kTransform |
                 CompositorMutableProperty::kOpacity));
-  EXPECT_TRUE(scrollLayer->elementId());
+  EXPECT_EQ(scrollLayer->elementId(),
+            createCompositorElementId(DOMNodeIds::idForNode(scrollElement),
+                                      CompositorSubElementId::Scroll));
 
+  // Root scroll layer gets document node id.
   WebLayer* rootScrollLayer = getRootScrollLayer();
   EXPECT_TRUE(rootScrollLayer->compositorMutableProperties() &
               (CompositorMutableProperty::kScrollLeft |
@@ -185,7 +192,9 @@ TEST_P(CompositorWorkerTest, plumbingElementIdAndMutableProperties) {
                (CompositorMutableProperty::kTransform |
                 CompositorMutableProperty::kOpacity));
 
-  EXPECT_TRUE(rootScrollLayer->elementId());
+  EXPECT_EQ(rootScrollLayer->elementId(),
+            createCompositorElementId(DOMNodeIds::idForNode(document),
+                                      CompositorSubElementId::Scroll));
 }
 
 TEST_P(CompositorWorkerTest, noProxies) {